eclipse c++ function defined in header could not be resolved -

i trying compile c++ program however, getting error

function 'argument' not resolved ...... semantic error 

however argument defined in app.h have included in project.

i have included header files going project > properties > c/c++ general > paths , symbols > includes. under gnu c++ clicking add, file system , putting in path files.

i can't figure out why getting error.

the line giving me error is:

arguments = {   argument ("input", "input image", "the input image.").type_image_in (),   argument ("ouput", "output image", "the output image.").type_image_out (),   argument::end }; 

and in 'app.h':

#define arguments   const mr::argument __command_arguments[] 

solution: closing project , reopening solved problem......

solution: closing project , reopening solved problem......